The windows of modern day automobiles and small trucks are normally formed as one piece whereby lowering of the window will provide an opening along the entire upper edge of the window. Prior to the advent of the one-piece window, many automobiles included a separate small vent window that could be opened without opening the larger window.
Various wind deflectors or guards have been proposed for closing a portion of the opening provided when the one-piece window is partially opened. Wind deflectors of this type are normally attached to a window frame to provide a fixed opening and thus cannot be adjusted to vary the size thereof. Examples of these types of fixed wind deflectors are illustrated in U.S. Pat. Nos. 3,915,078 and 4,089,256.